gitclone: keep local changes when there is an error during update

README.rst

@@ -403,6 +403,34 @@ In case of uninstall, buildout will keep the repository directory::
   Installing git-clone.
   destination directory already exists.
 
+If an error occurs during update, the error is catched to prevent buildout
+behavior of deleting parts it failed to update. One type of possible error is
+fetching from a non existant remote::
+  >>> write(sample_buildout, 'buildout.cfg',
+  ... """
+  ... [buildout]
+  ... parts = git-clone
+  ...
+  ... [git-clone]
+  ... recipe = slapos.recipe.build:gitclone
+  ... repository = http://git.erp5.org/repos/slapos.recipe.build.git
+  ... """)
+  >>> print system(buildout)
+  Installing git-clone.
+  ...
+  >>> cd(sample_buildout, 'parts', 'git-clone')
+  >>> print system('echo kept > local_change')
+  >>> git remote add broken https://git.erp5.org/repos/nowhere')
+  ...
+  >>> print system(buildout)
+  Updating git-clone.
+  ...
+  Unable to update:
+  ...
+  >>> print system('cat local_change')
+  kept
+
+
 Ignore SSL certificate
 ~~~~~~~~~~~~~~~~~~~~~~
 

slapos/recipe/gitclone.py

@@ -242,6 +242,7 @@ class Recipe(object):
     If user doesn't develop, reset to remote revision (or branch if revision is
     not specified).
     """
+    try:
       # first cleanup pyc files
       self.deletePycFiles(self.location)
 
@@ -255,6 +256,13 @@ class Recipe(object):
           self.gitReset(self.revision)
         else:
           self.gitReset('@{upstream}')
+    except:
+      if not self.develop:
+        raise
+      # Buildout will remove the installed location and mark the part as not
+      # installed if an error occurs during update. If we are developping this
+      # repository we do not want this to happen.
+      print 'Unable to update:\n%s' % traceback.format_exc()
 
 def uninstall(name, options):
   """Keep the working copy, unless develop is set to false.